Connecting to a network drains the battery. Even if the instrument is idle, if the periodic connection is enabled, the instrument will regularly wake up and attempt to connect to the server. Trying to connect at regular intervals will drain the battery in a short amount of time.
When that behavior is unwanted (for instance when the instrument is unused and in storage) pressing the Disable All button (see 4 Figure 13) will completely disable WiFi™ and email connectivity. If the instrument is idle with all its WiFi™ connectivity disabled, it can keep its battery for at least 6 months.